It is well known that rowing is a particularly good form of exercise. Land travel devices have been developed to be operated by a rowing motion. By way of example only, one such device is shown in U.S. Pat. No. 4,941,673 , issued Jul. 17, 1990.
The difficulty encountered with a land travel rowing device such as that shown in the '673 patent is that, although possible, it is difficult to use one's arms to both row and steer at the same time.